This study will evaluate the safety and biochemical efficacy of a human neutrophil elastase inhibitor (CE-1037) in adult subjects with cystic fibrosis. This study involves the randomization of 15 subjects to either the HNE inhibitor CE 1037 or placebo, this is administered by continuous IV infusion for 168 hrs or 7 days. Each subject will be an inpatient in the gcrc for 9 days. Each subject will undergo 2 bronchoscopic lavages during this period. This will provide information regarding the transmission of the hne from the venous system to broncheal-alveolar cells. Efficacy will be measured by the transmission of the hne to bronchial aveolar cells as well as an increase in spirometry values such as FVC and FEV.